Generally, in an automatic transmission and a continuously variable transmission, an input torque of an engine is determined by a transmission control unit using an engine RPM signal, a throttle valve opening signal, and an input speed signal of the transmission. The input torque is transmitted to each control means to aid in improving the shifting operation.
This method of determining input torque, however, has a drawback in that since signals which are not closely related to the input torque of the transmission are used as input signals by the TCU to determine input torque, the possibility of error is increased, resulting in deterioration of the shift quality in the case of the automatic transmission and disallowing pressure of a drive or driven pulley to be optimally controlled in accordance with changes in running condition in the case of the continuously variable transmission.